Stanford is a member of which NCAA conference?

Stanford University is a member of the Pac-12 Conference, which is one of the premier conferences in NCAA Division I athletics. This conference, founded in 1915, comprises institutions primarily located in the western United States, promoting a high level of competition in various sports, including basketball. Stanford has a storied history within the Pac-12, contributing to both the athletic tradition and academic integrity of the conference.

The other conferences listed, such as the Big 12, the American Athletic, and the Mountain West, have different member institutions and geographic focuses, which is why they are not relevant to Stanford's affiliation. The Pac-12 specifically features a combination of academic excellence and athletic prowess, making it the correct answer for Stanford's conference membership.